If you (own or) are considering buying an (used) electric vehicle (BEV or PHEV), one of the most important long-term factors to understand is battery degradation. Much like a smartphone battery loses its ability to hold a full charge over time, EV batteries also degrade – but the process is slower and much more complex.

In this article, we’ll explore:

• What EV battery degradation means and how it happens
• Real-world examples using a 2016 Tesla Model S 85D
• How to calculate degradation
• What the results actually mean
• How charging habits, especially fast charging, impact battery longevity
• Tips to extend your EV battery lifespan

Whether you’re an EV owner or simply exploring the topic, this guide offers fact-based insights in clear, simple English to help you make informed decisions.

What Is Battery Degradation?

Battery degradation refers to the gradual loss of capacity in a battery over time, meaning it can’t store or deliver as much energy as it could when new. For EVs, this typically translates into reduced driving range per full charge.

Degradation is natural and expected in all lithium-ion batteries, but the rate and impact vary depending on multiple factors like:

Battery chemistry
Environmental temperature
Driving habits
Charging practices
Most EVs lose between 1% to 2% of capacity per year, though the exact numbers depend on how the vehicle is used and maintained.

Case Example: 2016 Tesla Model S 85D

To better understand how degradation works, let’s look at a real-life scenario involving a 2016 Tesla Model S 85D:

Official factory-rated range (EPA): 435 km (270 miles)
User-observed range in 2020: 427 km (265 miles) after 4 years
User-observed range in 2025: 383 km (238 miles) after 9 years
This shows that even after nearly a decade, the car retained 88% of its original range, which is quite healthy.

Let’s break this down with simple math.

How to Calculate Battery Degradation

To calculate degradation, we use this formula:

Degradation % = ((Original range – Current range) / Original range) × 100

1. First 4 Years (2016 to 2020)

Original range: 435 km
2020 range: 427 km

Degradation = ((435 - 427) / 435) × 100 = 1.84%
Annual average = 1.84% / 4 = 0.46% per year

2. Next 5 Years (2020 to 2025)

2020 range: 427 km
2025 range: 383 km

Degradation = ((427 - 383) / 427) × 100 = 10.31%
Annual average = 10.31% / 5 = 2.06% per year

3. Total Over 9 Years

Degradation = ((435 - 383) / 435) × 100 = 11.95%
Annual average = 11.95% / 9 = 1.33% per year

What does this mean? Despite regular usage and aging, the vehicle still retains nearly 90% of its original range. This indicates good battery health and proves that EV batteries can be long-lasting with proper care.

The Impact of Charging Habits

One major factor that influences battery degradation is how you charge your EV. There’s a common question among EV owners:

“Does fast charging harm EV batteries?”
The short answer: Yes, over time, it can contribute to faster degradation.

In a deep-dive article, I break down how repeated fast charging heats up the battery, accelerating chemical aging. Slower, Level 2 charging (AC) generates less heat and puts less stress on battery cells, making it a more battery-friendly method for daily use.

Summary of Charging Best Practices:

• Use Level 2 Mode 3 (AC) charging for daily needs
• Avoid fast DC charging unless necessary (e.g., on road trips)
• Keep battery between 20% and 80% for regular use
• Avoid letting the battery sit at 0% or 100% for long periods
• Park in shaded or temperature-controlled environments when possible

How You Can Monitor and Manage Degradation

Most EVs allow you to view your current estimated range when fully charged. While it’s not an exact science, tracking this number over time can help you spot trends.

There are also third-party tools and apps that can give deeper insight into:

• Charge cycles
• Battery health scores
• Charging patterns
• Cell-level analysis (for Teslas via services like TeslaFi or Scan My Tesla)

Key Takeaways

• Battery degradation is normal, but typically slow (1-2% per year)
• A 2016 Tesla Model S 85D shows strong performance even after 9 years, with ~12% degradation total
• Proper charging habits, especially avoiding frequent fast charging, significantly impact battery lifespan
• Monitoring your vehicle’s range over time helps you stay informed

Final Thoughts

If you’re worried about EV battery degradation, you’re not alone. But the good news is that real-world data shows modern EVs can last a long time without significant range loss. By adopting mindful charging practices and understanding what the numbers actually mean, you can confidently enjoy your EV for years to come.

For more on EVs, sustainability, and minimalist travel living, check out my other articles.

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